The present invention relates to a switch and particularly to a spring-loaded push-button switch with a rotary contact.
In the automotive industry push-button switches are used extensively for map lamps and other overhead lights inasmuch as the switching action is relatively easy to accomplish during the operation of a vehicle or as a passenger. There exists several patents on a wide variety of contact arrangements for such switches including U.S. Pat. No. 3,694,603 which discloses a rachet-type mechanism for rotating and extending and retracting a moveable contact. The difficultly with switches made according to the prior art are that with the rachet push-button mechanism employed, as a switch is actuated, the lights will momentarily flicker to an on or off position until the next stable position of the longitudinally moveable contact is reached. This is inherent in the nature of the rachet mechanism and the fact that the moveable contact typically extends beyond a stable position and then returns to a stable position. The flickering is somewhat objectionable to the user inasmuch as it appears that the switch is defective when in fact it is simply the nature of the switch operation.
Also with the rachet-type prior switch designs, the switch contacts themselves although providing some relative motion between the moveable and fixed contacts do not provide a self-cleaning wiping action to maintain the contacts clean and therefore improve the electrical conductivity between the moveable and fixed contacts.